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DISCUSSION => General Topics => Topic started by: achtungE30 on January 25, 2007, 10:54:06 AM

Title: My speedo needs recalibration!!!
Post by: achtungE30 on January 25, 2007, 10:54:06 AM
I am fairly certain my speedo is off by 8-10mph once i pass the 55-60mph threshold...i know this because at an indicated 80mph, i am constantly tailgated and passed by angry drivers in newer cars. At that speed indicated, my seat of the pants tells me im i70-75.

I once approached a toll plaza at 50mph and it indicated 42mph.

I will have my cluster out soon to fix the odometer gear, while its out, is there any way to recalibrate the speedo while im at it? I've read years ago that e36s had a similar problem to which some dealer techs just bent the speedo needle a few deg backwards and it fixed the problem, although im not too sure i want to try this if someone has a better explanation.

EDIT, im back on 14" basketweaves.
Title: My speedo needs recalibration!!!
Post by: Gunni on January 25, 2007, 11:48:29 AM
You can remove the needle and put it back a little higher,
then you should be within specs,
I had to do that to one fuel gauge so the amber light came on when it hit the red zone,
Title: My speedo needs recalibration!!!
Post by: achtungE30 on January 25, 2007, 01:28:16 PM
well dont i need to do the reverse of that since my mph now is reading higher than it actually is?

how do i do that if its pinned at 0 now and resting at the needle stops?
Title: My speedo needs recalibration!!!
Post by: Gunni on January 25, 2007, 03:10:11 PM
I forgot about the needle stop, maybe you should try finding a speedometer calibrator
Title: My speedo needs recalibration!!!
Post by: Wizard on January 25, 2007, 03:15:24 PM
Have heard of this problem a lot with our cars....every one blames it on tire size (BULL)...Mine is running about 10% higher also....Still haven't found a solution....I have an extra 4.10 -- I may try to switch over the speedo sensor and see if that may work. I do not see any calibration screw on the back of the actual speedometer...
Title: My speedo needs recalibration!!!
Post by: kowalski on January 25, 2007, 03:20:12 PM
http://www.miata.net/garage/tirecalc.html

stock tires are 195/65/14.

and yes it is because of tire size, most people arn't running stock tires, and this is why their speedo is off. My tires are 205/40/17 and that is why mine reads faster then i'm doing.
Title: My speedo needs recalibration!!!
Post by: Wizard on January 25, 2007, 03:47:41 PM
Canada=kilometers.......You guys are always off...J/K :D

I run 195/65/14's so I should only be off 3.2% but mine is way higher....10% according to radar...
Title: My speedo needs recalibration!!!
Post by: silverblades181 on January 25, 2007, 06:09:03 PM
From experience, all my E30s (4) speedos were optimistic by 5-10%. Must be in the algorithm bmw used to calculate the oscillations in the speed sensor in the diff.
Title: My speedo needs recalibration!!!
Post by: johna on January 27, 2007, 05:48:15 PM
You can buy a device that alters the electronic signal from the differential such as this one... http://www.jaycar.com.au/productView.asp?ID=KC5435 (http://www.jaycar.com.au/productView.asp?ID=KC5435)
Title: My speedo needs recalibration!!!
Post by: BrandC on January 27, 2007, 09:57:37 PM
I constantly had gauge cluster problems on my VW MK3 VR6 (VDO). Then I found out about these guys:

http://www.tacomaspeedometer.com/index.htm

I sent out the cluster on my own dime, and it was $65 shipped after that to have my entire cluster recalibrated. Ask for a guy named Eddie.
Title: My speedo needs recalibration!!!
Post by: sheepdog on January 29, 2007, 02:00:37 PM
Find someone with a gps, that is how I  did it.

195/60-r14's  will be off by 10%
At 55 on the speedo you are doing 50, at 66 you are doing 60, 77 equals 70, etc..

4000rpm is almost exactly 80mph.




Moving the needle only works if it is is off by  the same amount all the time. Most are of by a ratio/percentage, in which case only a recalibration will help. Best just to know how far off it is.
Title: My speedo needs recalibration!!!
Post by: Alpine003 on January 29, 2007, 02:16:54 PM
Quote from: sheepdog;18395
Find someone with a gps, that is how I  did it.


You can also go through school zone or construction areas that have the radar setup to clock your speed and display it on the sign "Your speed limit is: "

Obviously, do not whizz by when school is in session or construction workers are present. :p
Title: My speedo needs recalibration!!!
Post by: sheepdog on January 30, 2007, 10:04:59 PM
Quote from: Alpine003;18397
You can also go through school zone or construction areas that have the radar setup to clock your speed and display it on the sign "Your speed limit is: "

Obviously, do not whizz by when school is in session or construction workers are present. :p


Not as good, you have few speeds to get a good reading, you have  to take  your eyes off the road and focus on the sign and your speed. You also may see  the speed of the car next to you.
Title: My speedo needs recalibration!!!
Post by: Alpine003 on January 31, 2007, 11:10:14 AM
Quote from: sheepdog;18514
Not as good, you have few speeds to get a good reading, you have  to take  your eyes off the road and focus on the sign and your speed. You also may see  the speed of the car next to you.


It worked for me. I can actually see the instrument cluster and sign at the same time. Holding steady throttle is no big deal for me. I know some hardcore "city" people that never take long highway trips and are unable to hold a steady speed though...;)
Title: My speedo needs recalibration!!!
Post by: ///Motorsport on February 01, 2007, 03:08:06 PM
I have same issues, running Azenis on weaves.  
However, Seeing that I am 5 mph off at 25 in a 25 radar screen zone doesnt help me much.  I'm worried about how off my speedo is up aorund highway speeds.

 Just gonna cruise next to a friend while on the cell phone...
Title: My speedo needs recalibration!!!
Post by: sheepdog on February 01, 2007, 05:13:47 PM
Quote from: ///Motorsport;18628
I have same issues, running Azenis on weaves.  
However, Seeing that I am 5 mph off at 25 in a 25 radar screen zone doesnt help me much.  I'm worried about how off my speedo is up aorund highway speeds.

 Just gonna cruise next to a friend while on the cell phone...


Exactly my point, what it is off at 25 is not the same as 55.
Using a buddy may not help if theirs is off too.
Title: My speedo needs recalibration!!!
Post by: Alpine003 on February 02, 2007, 12:48:24 PM
Quote from: sheepdog;18645
Exactly my point, what it is off at 25 is not the same as 55.
Using a buddy may not help if theirs is off too.


That's because you guys need to speed through highway construction zones at 90mph +. :p

I did the buddy method alongside my friend's 2004 E46 with my Tii. That probably is the best and safest method, come to think of it.
Title: My speedo needs recalibration!!!
Post by: Kilawin on March 03, 2008, 06:56:07 PM
Try adjusting the pot.  

http://www.r3vlimited.com/board/showthread.php?t=95733
Title: My speedo needs recalibration!!!
Post by: tjts1 on March 03, 2008, 07:13:11 PM
All our speedos have a fixed 5mph error built in. Look at your speedometer when the car is standing still. The needle sits about 5mph below the 10mph mark. With 195/65R14 tires my GPS shows the speedometer to be 5mph too fast at all speeds. When I switch over to the 195/60R14 tires, I can add a 3% error the the fixed 5mph error. I've had 2 GPS devices in this car, they always show the same thing.
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